The present disclosure relates to a coordinate measuring device. One set of coordinate measurement devices belongs to a class of instruments that measure the three-dimensional (3D) coordinates of a point by projecting a pattern of light to an object and recording the pattern with a camera.
A particular type of coordinate-measuring device, sometimes referred to as an accordion-fringe interferometer, forms the projected pattern of light by the interference of light of diverging wavefronts emitted by two small, closely spaced spots of light. The resulting fringe pattern projected onto the object is analyzed to find 3D coordinates of surface points for each separate pixel within the camera.
An implementation of an accordion fringe interferometer is one in which a diffraction grating is moved using piezoelectric actuator, a capacitive feedback sensor, a flexure stage, multiple laser sources, and multiple objective lenses. This type of accordion fringe interferometer is relatively expensive to manufacture and relatively slow in performing measurements. What is needed is an improved method of finding 3D coordinates.